Tucked away behind that fresh pencils, new start, September reset energy, does anyone else feel a bit... off at this time of year? If so, you’re not alone, and you’re not imagining it.
While the arrival of September promises the beginning of autumn, it brings with it some complications to the ‘hooray, a new season!’ narrative we like to tell ourselves. Right now, after a long, (very) hot summer, we’re firmly in a moment of in-between, unpredictable weather. One minute, it’s chucking it down, the rain pleasantly drumming the windows, then suddenly, it’s baking hot. Day-to-day, the skies go from clear blue to muddied grey.
As well as making it very difficult to work out what to wear every day, this strange, unpredictable, in-between-y weather has an impact on our mental wellbeing.
Trevor Harley is Emeritus Professor of Psychology at the University of Dundee. In his recent book, Head In The Clouds, he explores all facets of how the weather affects our mental health. He notes that this particular September follows a ‘wonderful summer’, which could make this year’s transition into autumn especially tricky.
‘If you like it hot and sunny, southern Britain has certainly been the place to be,’ Trevor tells Good Housekeeping. ‘Summer 2026 was provisionally the hottest on record for the UK, and England and Wales were exceptionally warm and sunny. Scotland was closer to average for sunshine, particularly towards the end of the season.’
As we’ve entered September, there are some hangover temperatures from those hot months... but also ‘thunderstorms, much-needed rain, sunless days and windy weather,’ notes Trevor. ‘September is, by meteorological convention, the beginning of autumn. This year – rather like that other famous British summer, 1976, whose long drought ended dramatically at the end of August and beginning of September – the change has seemed particularly noticeable.’
The lack of predictability – and a sense of receiving mixed signals from the world around us – does not make for an ideal mental state. As Trevor points out: ‘The shortening day length says autumn. The declining height of the Sun in the sky says autumn. The temperature may still say summer. The vegetation says something between late summer and early autumn. The weather may alternate between summer-like high pressure and increasingly autumnal spells of wind and rain. And the social calendar emphatically says autumn.’
The human brain likes certainty and clarity. We function like prediction machines, and prefer when our predictions turn out to be true. When this doesn’t happen – such as when we dress for what we think the weather should be like at this time of year, and end up too hot or too cold – we can find it unsettling. Uncertainty of any type has been shown to worsen existing mental health conditions and cause us psychological distress.
We tend to still be caught off-guard by this weird point in the year despite previous experience of Septembers being confusing, weather-wise. There’s a meteorological explanation for this, because September is, quite simply, a strange, mismatched time in terms of what the natural world looks and feels like. ‘Across the UK, September is normally warmer than May, even though May is much sunnier,’ Trevor tells us. ‘In the current 1991-2020 climate averages, May receives roughly 190 hours of sunshine across the UK, compared with only about 130 hours in September. Yet the average daytime maximum is about 15°C in May and nearly 17°C in September. The seasons lag behind the Sun. By September the land and, especially, the surrounding seas have accumulated months of summer warmth. In May, by contrast, we have emerged only recently from winter. So September can feel surprisingly warm beneath a Sun that is becoming noticeably weaker. We are, in other words, between seasons.’
That in-between-ness has a word that psychologists often reference: liminality. ‘A liminal period is one in which we have left one state but haven’t fully entered the next,’ explains Trevor. ‘Adolescence is an obvious example, starting university another: normal rules and routines can seem temporarily suspended.’
And this point in the year can feel very, very liminal. We’re going through multiple transitions – seasonal, logistical, weather-wise – all at once. Trevor explains that transitions of any kind ‘may bring uncertainty, heightened awareness of what is changing, disruption of familiar routines, nostalgia for what is disappearing and anticipation — sometimes anxiety – about what comes next.’
Some people will be more able to handle this in-betweenness than others. 'People with ASD (autism spectrum disorder), in particular, often report finding uncertainty and unexpected change difficult, and research has found a strong relationship between intolerance of uncertainty and anxiety in ASD,’ Trevor notes. Neurotypical people can still find this difficult. Generally having a high intolerance of uncertainty (IU), which can be the case for those without diagnosed mental health conditions, has been shown to make negative emotion states feel worse and positive emotion states feel lessened.
Then you bring seasonal affective disorder (SAD) into the mix. Days shorten, the sunset gets earlier, there’s less light. Trevor says: ‘For some people that matters psychologically. As the days shorten, some of us notice changes in energy, sleep, appetite or mood. Others feel invigorated by autumn and are relieved to escape the heat of summer. People vary enormously, and it would be wrong to suggest that autumn inevitably makes us miserable.
‘People with SAD are particularly vulnerable at this time of year. SAD is not simply feeling fed up because it is raining. It is a recurrent form of depression with a seasonal pattern, usually beginning during autumn or winter and improving in spring or summer. In the terminology used in modern psychiatric diagnosis, it is usually described as major depressive disorder “with seasonal pattern”.’
A significant portion of poor mood as we enter autumn is thought to be down to the decrease in light, which can also mess up our sleep (which, in turn, impacts our mental health... it’s a bad cycle). ‘Light affects us because it is one of the most important signals used by the brain to regulate our internal biological clock,’ Trevor explains. ‘Light entering the eyes provides information to the brain about the time of day and helps synchronise our circadian rhythms – the roughly 24-hour rhythms affecting sleep, alertness, hormone secretion and many other physiological processes. The biology of SAD isn’t completely understood. Disturbances of circadian timing appear to be involved, and serotonin and melatonin systems have also been implicated. It is much more complicated than the familiar idea that sunlight simply boosts a “feelgood chemical”.’
The in-between weather of September can add on a layer of self-blame and shame. When it seems like everyone else is happily cracking on with their autumnal resets or enjoying the warm weather, you can feel like a bit of a September failure in comparison. You start to wonder: what’s wrong with me? Why can’t I just get on with it like everyone else can?
And there’s anticipatory anxiety, too. While not everyone hates winter, many people do dread (or even fear) the colder, shorter days. That’s definitely the case for Trevor, who says: ‘At this in-between time of year, I can see winter approaching. Each evening is a little darker than the one before. I know what is coming, and sometimes the anticipatory anxiety is almost worse than the thing itself – a bit like a visit to the dentist.’
All in all, then, there’s a whole host of factors that could make your mood go a bit skew-whiff at this time of year, in this strange weather moment. If you’re finding things tough, you’re not the only one – and there are legitimate reasons behind the struggle, so don’t beat yourself up.
How to care for your mental health in this in-between period
There are steps to take to protect your mental health from the impact of our reentry into autumn. Trevor recommends the below:
Get daylight, particularly early in the day.
‘Going outdoors exposes us to much brighter light than ordinary indoor lighting, even on a cloudy day. Add a walk, run or other activity and you gain the psychological and physical benefits of exercise as well.’
Consider bright-light therapy if you suffer from winter SAD
‘Light boxes are much smaller and cheaper than when I first started using them in the 1990s. Treatment commonly involves exposure to a properly designed bright light box in the morning. There is evidence that bright-light therapy can help SAD, although UK clinical guidance notes that the evidence is not perfect. Anyone with an eye condition, bipolar disorder, or taking medication that increases sensitivity to light should seek medical advice before using one. I have three light boxes around the house and use them in the morning.’
Keep nights dark
‘Bright light late in the evening can shift our biological clock in the wrong direction. Turning down household lighting and reducing bright screen light before bed can help reinforce the contrast between day and night.’
Consider vitamin D
‘In the UK, the NHS recommends that adults consider taking 10 micrograms of vitamin D daily during autumn and winter, when sunlight is generally insufficient for us to make enough through our skin. Vitamin D is important for health, but supplements should not be regarded as a proven treatment for SAD. More evidence is needed.
Seek support
‘Persistent depression is not something we should simply put down to the weather. If low mood, loss of pleasure, tiredness or other symptoms are significantly affecting your life, seek professional help.’
Do a reframe
’There is another approach that matters to me: learning to accept, and perhaps even embrace, seasonal change. For years, I hated the way that, in winter, the Sun disappears behind a hill near my home at around three in the afternoon. I saw the early darkness mainly in terms of what it stopped me doing. I have gradually learned to think differently. Darkness can mean going indoors, getting warm, reading a book and resting. Autumn and winter aren’t failed versions of summer. They are different seasons with different possibilities.
‘Perhaps, this in-between season can be useful. Instead of seeing September merely as the loss of summer and the beginning of the long slide into winter, we can treat it as a transition: a chance to change routines, begin something new and think about how we want to spend the darker half of the year.’
